Method of catalytic oxidation in vapour phase implemented in multiple-tubular reactor

FIELD: heating.

SUBSTANCE: invention concerns improved method of catalytic oxidation in vapour phase which supplies effective removing of reactionary heat, excludes hot spot formation, and supplies effective receipt of base product. Method of catalytic oxidation is disclosed in the vapour phase (a) of propylene, propane or isobutene by the instrumentality of molecular oxygen for receiving (meth)acrolein, and/or oxidation (b) of (meth)acrolein by molecular oxygen for receiving (meth)acryl acid, by the instrumentality of multiple-tubular reactor, contained: cylindrical reactor vessel, outfitted by initial material supply inlet hole and discharge hole for product, variety of reactor coolant pipes, located around the cylindrical reactor vessel and used for insertion the heat carrier into cylindrical reactor vessel or for removing the heat carrier from it, circulator for connection of variety loop pipeline to each other, variety of reaction tube, mounted by the instrumentality of tube reactor lattices, with catalyst. Also multiple-tubular reactor contains: variety of partitions, located lengthways of reaction tubes and used for changing heat carrier direction, inserted into reactor vessel. According to this heat carrier coolant flow is analysed and there are defined zones in reactor which have heat-transfer coefficient of heat carrier less than 1000 W/(m²·K); also reaction of catalytic oxidation is averted in the vapour phase in mentioned zones of reactor and reaction of catalytic oxidation is implemented in the vapour phase in reactor.

EFFECT: receiving of improved method catalytic oxidation in vapour phase which supplies effective removing of reactionary heat, excludes hot spot formation, and supplies effective receipt of base product.

3 cl, 6 dwg, 2 ex

The present invention relates to a method of catalytic oxidation in the vapor phase. The present invention is preferably used for the oxidation of propylene, propane or isobutylene with molecular oxygen for efficient obtaining the (meth)acrolein or (meth)acrylic acid.

The level of technology

Novotrubny the reactor used to carry out the reaction in which the source material is in contact with a solid catalyst loaded in the reactor. Novotrubny reactor regulates the temperature of the reaction due to the effective removal of a significant amount of heat produced by the reaction of catalytic oxidation in the vapor phase, in which the oxidizable substance is in contact with molecular oxygen in the presence of the solid catalyst. Typically, the reactor is used when there is a need to protect the catalyst from the destruction that occurs under the high temperatures of the reaction heat.

In this novotrubnom reactor liquid for cooling (hereinafter, the link is to the heat transfer medium circulates outside the site of the reaction tubes (i.e. on the side of the case) to maintain the temperature required for the reaction, and the heat exchange between the process stream (in the reaction of catalytic oxidation in the vapor phase is a process-gas and coolant is simultaneously the built in heat exchangers, widely used in chemical plants. This method protects the catalyst in the pipe from damage resulting from local overheating of the catalytic layer (formation of hot spots).

However, the amount of reaction heat released during the reaction of catalytic oxidation in the vapor phase, is so great that it leads to the destruction of the catalyst because of the frequently occurring hot spots and can cause uncontrollable reaction because the temperature of the catalyst. All this can lead to complications, such as the unsuitability of the catalyst for use.

Have been proposed numerous ways, limiting the appearance of hot spots in novotrubnom the reactor used for the reaction of catalytic oxidation in the vapor phase. For example, in Japan patent JP 08-92147 described the way in which the flow direction of the coolant inside the reactor vessel and the direction of flow of the source gas in the reactor parallel to each other. In addition, the coolant flow can be tortuous direction using partitions for guiding the thread up. Thus, the temperature becomes uniform with the temperature difference between the temperature at the inlet and outlet, part 2-10°and less. However, in this method focuses on the difference t is Imperator coolant. Thus, in the described reactor with uneven heat transfer coefficient, the disadvantage is the appearance of hot spots in the area with a low coefficient of heat transfer.

In the Japan patent JP 2000-93784 And describes how to limit the formation of hot spots where the threads unreacted source gas and the coolant is directed downward parallel to each other in order to avoid the accumulation of gas that does not contain the coolant. The following describes a method of forming a catalyst near the catalytic layer, which is most easily affected reversible destruction by feeding a source gas into the reactor through his upper part to pass down through the layer of catalyst reaction tubes.

However, in this method, the focus is on the relationship of the flow of the source gas with the coolant. Thus, the disadvantage of this method lies in insufficient removal of the reaction heat, which leads to the formation of hot spots, if the flow rate of the coolant and the heat transfer coefficient is low.

Also, according to another Japan patent 2001-137689 method limit the formation of hot spots by location of partitions, changing the flow direction of the coolant and the reaction tubes. In novotrubnom reactor coolant for cooling the reaction heat circulates through the Tinqueux reactor. Due to the presence of host reaction tubes and baffles in the flow path that passes through the wall of the housing, the coolant flows separately in the site of the reaction tubes in the space between the partitions and the site of the reaction tubes in the space between the partitions and the reactor vessel. However, the coolant passing through the part other than the site of the reaction tubes cannot be used for cooling the reaction tubes, and thus the amount of fluid should be reduced. In addition, in JP patent 2001-137689 contains information regarding the flow rate of the coolant in General, and there is no information about the heat transfer coefficient. Therefore, the problems related to the hot spots that need to be resolved taking into account the heat transfer coefficient.

In novotrubnom the reactor, the reaction heat, which occurs inside of the reaction tube, is removed by the circulation of the coolant. Therefore, if the reaction heat is not effectively removed, are formed in the catalytic layer of hot spots and reduces the yield of the target product, deteriorating the catalytic activity, etc.

The temperature distribution in the catalytic layer is determined by the balance between the amount of heat produced inside the reaction tube, and the amount of heat delivered to the heat carrier. In accordance with this would be the and an attempt is made to reduce the temperature in the zone of hot spots, in which the coefficient of heat transfer from the coolant was increased by increasing the flow rate of the coolant. However, if the flow rate of the coolant is increased to values greater than necessary, there is an increase in the size of the circulation pump for the coolant. Moreover, the higher the power of the circulation pump coolant, the greater are the problems of increased cost of this operation.

Description of the invention

Thus, the present invention is to provide a method of catalytic oxidation in the vapor phase, carried out in novotrubnom the reactor, including the effective removal of reaction heat by using the appropriate quantity of circulating coolant, preventing the formation of hot spots, the effective yield of the desired product, increasing the service life of the catalyst without affecting catalytic activity.

There have been several studies for the development of this method was the analysis of flow and heat transfer fluid on the wall of the housing novotrubnogo reactor, the amount of which was increased. In the result, it was found that the method of catalytic oxidation in the vapor phase allows to achieve the objectives above, if the reaction of catalytic oxidation is carried out in n the global phase under such conditions, in which the coefficient of heat transfer fluid has a special significance, and this discovery was developed the present invention.

Thus, the present invention represents:

(1) a Method of catalytic oxidation in the vapor phase of the substance intended for oxidation using a gas containing molecular oxygen is carried out in novotrubnom reactor, which comprises a cylindrical reactor vessel equipped with inlet port for supplying the source material and an outlet opening for the product; many circulating tubes arranged around the cylindrical body of the reactor and used for the introduction of fluid into the cylindrical reactor or for removal from the coolant; a coolant circulation device for connection of a variety of circular pipes with each other; many reaction tubes installed with the help of numerous tubular reactor lattices, in which are placed the catalyst; as well as many partitions in the longitudinal direction of the reaction tube and used for changing the direction of the coolant introduced into the reactor vessel, the method which comprises carrying out the reaction of catalytic oxidation in the vapor phase under conditions in which the heat transfer coefficient of the heat carrier is 1000 W/(m² K) or higher.

(2) a Method of catalytic oxidation in the vapor phase under paragraph (1), which involves the oxidation of propylene, propane or isobutylene with molecular oxygen to produce (meth)acrolein and/or oxidation of (meth)acrolein to obtain (meth)acrylic acid.

Brief description of drawings

1 shows an implementation option novotrubnogo heat exchanger reactor used in the method of catalytic oxidation in the vapor phase.

Figure 2 shows a variant implementation of the partitions used in novotrubnom reactor in accordance with the invention.

Figure 3 shows a variant implementation of the partitions used in novotrubnom reactor in accordance with the invention.

Figure 4 shows a top view novotrubnogo reactor in accordance with the invention.

Figure 5 shows a variant implementation novotrubnogo heat exchanger reactor used in the method of catalytic oxidation in the vapor phase according to the present invention.

Figure 6 shows in an enlarged scale view of the intermediate tube, the separating case novotrubnogo reactor according to Figure 5.

The best option of carrying out the invention

Hereinafter, the present invention is described in detail.

The present invention relates to a method of catalytic Oka the population in the vapor phase of the substance, intended for oxidation using a gas containing molecular oxygen is carried out in novotrubnom reactor, comprising a cylindrical reactor vessel equipped with inlet port for supplying the source material and the discharge of the product; many of the circulation pipes located around the cylindrical reactor and used for the introduction of fluid into the cylindrical reactor vessel for removing the coolant; a coolant circulation device for connecting multiple coolant pipes to each other; a lot of the reaction tubes, in which the catalyst is installed using a variety of pipe arrays reactor, and a lot of partitions arranged in the longitudinal direction of the reaction pipe and used to change the direction of the coolant introduced into the reactor vessel, the method differs in that the reaction of catalytic oxidation in the vapor phase is carried out in such conditions that the heat transfer coefficient of the heat carrier is 1000 W/(m²·K) or higher.

In the present invention, the benzene or butane is used as a substance subject to oxidation, this product is subjected to catalytic oxidation in the vapor phase with a gas containing molecular oxygen, to receive maleic anhydride. The invention is also used when at least xylene or naphthalene used as a substance subject to oxidation, and which is subject to catalytic oxidation in the vapor phase with a gas containing molecular oxygen, to obtain phthalic anhydride.

More preferably, the present invention uses propylene, propane or isobutylene as a substance subject to oxidation, and which is subject to catalytic oxidation using a gas containing molecular oxygen, to obtain a (meth)acrolein (hereinafter, the link is at the preliminary stage (first stage reaction). (Meth)acrolein obtained in the preliminary stage of the reaction, and then used as a substance subject to oxidation, and is subject to catalytic oxidation in the vapor phase with a gas containing molecular oxygen, to obtain a (meth)acrylic acid (hereinafter, reference is given to the next stage (second stage) reaction).

In the present invention, the heat transfer coefficient of the coolant is determined, in particular, the analysis of the flow using the computer.

The above analysis of coolant flow can be carried out by the method of simulation: it is determined by the design of the reactor, such as the placement is errordoc and the reaction tubes, and the hole for the coolant supply; specify options for the heat carrier, such as its physical properties and flow rate. More specifically, the flow direction and the flow velocity of the coolant is determined by calculation based on the equations of conservation of momentum, conservation of mass and conservation of enthalpy, etc. In the present invention, the analysis may be performed using CFX (developed by AEA Technology Plc) as a software for the analysis of stream.

Therefore, the analysis of coolant flow allows you to designate a portion of the flow having a low coefficient of heat transfer fluid.

In addition, in the present invention the reaction of catalytic oxidation in the vapor phase flows in such conditions, in which the heat transfer coefficient of the heat carrier is 1000 W/(m²·K) or higher. In particular, the reaction tube located in the area with a heat transfer coefficient of less than 1000 W/(m²·K)is closed thereby to prevent the leakage of gas or in the reaction tube is not download the catalyst, so it did not leak response. With the same purpose in that zone is not set itself the reaction tube. These measures help to avoid violations of the reaction due to an excessive increase in the temperature in the reaction tube in the zone with n skim heat transfer coefficient of the heat carrier.

Also, the space between the partitions located on the side of the reactor, where flows the coolant and reactor vessel or the space between the baffles and the reaction tube perform a narrowing or set the jumper to reduce the amount of coolant flowing from this space. As a result, increases the heat transfer coefficient of the coolant. Similarly, the reaction of catalytic oxidation in the vapor phase can be performed by increasing the flow rate of the coolant or changing the size of the partition in order to fix the area with a coefficient of heat transfer below 1000 W/(m²·).

Figure 1 shows the first variant implementation novotrubnogo heat exchange reactor, in which the method of catalytic oxidation in the vapor phase according to the invention.

In case 2 novotrubnogo reactor of the reaction tubes 1A, 1b and 1C are installed by attaching the pipe to the gratings 5A and 5b. An inlet for supply of the source material, which is input to the reaction of the source gas, and an outlet opening for the product, which is the outlet for the products that are shown, respectively, in positions 4A and 4b. However, the gas flow can be in any direction. On the outer peripheral part of the reactor has a circulation pipeline for the introduction of coolant. The coolant is supplied under pressure by means of the circulation pump 7, so that the coolant was held up in the reactor vessel for circulating pipe 3A and returned to the circulation pump through the circulation pipe 3b, once the flow direction is changed. This allows you to create alternative construction: hollow walls 6a, each having a corresponding hole in the Central part of the reactor vessel, and a hollow partition walls 6b located so that cracks were formed between the respective hollow partition walls 6b and the peripheral part of the reactor vessel. Part of the coolant that absorbs the reaction heat, is cooled in a heat exchanger (not shown) through an exhaust pipe, located in the upper part of the circulating pump 7, and then fed into the reactor through the feed line 8A for the introduction of coolant. The temperature set by temperature control or velocity of flowing fluid is supplied through pipe 8A in accordance with the indication of thermometer 14.

Although the process of regulating the temperature of the coolant depends on the characteristics of the used catalyst, it is preferable to carry out the temperature control so that the temperature difference between the heat carrier, which is vodusek pipe 8A, and coolant in the outlet pipe 8b, was 1-10°C, preferably 2-6°C.

Bearing plate (not shown) preferably located on the plates of the hull within the corresponding annular pipelines and 3b, in order to minimize the velocity distribution of the coolant flow around the circumference. Perforated plates or plates having slots, are used as load-bearing plates. Flow adjust so that the open area of the perforated plate or cracks could be changed and so that you can enter the coolant at a constant speed over the entire periphery. 3A temperature inside the annular pipe (3A or preferably and pipeline 3b) see on the established two or more thermometers 15.

The number of partitions in the reactor vessel, preferably equal to three (two partitions of type 6A and one type 6b) or more, but their number is not limited. Hereinafter, the description relates to a reactor (1)having three partitions, which are given by way of example.

The presence of partitions does not allow the coolant to pass up and changes the flow direction of the coolant in the lateral direction relative to the axial direction of the reaction tube. Thus, the coolant is concentrated in the Central part, p is remesas from the periphery of the reactor vessel, and then turns back near the holes of the partitions 6A and sent to the periphery, and then reaches the outer cylindrical part of the body. The fluid rotates around the outer periphery of the partition walls 6b and again fed to the Central part and moves up through the hole walls 6A to the outer periphery along the top tube 5A of the reactor, then using a circulating pump moves along the circular pipe 3b.

In addition, the partitions 6A and 6b have holes to install them in the reaction tubes, and between the partitions and the casing is provided free space in case of overheating of the reactor. Therefore, a certain amount of fluid may pass through these openings and space, which can lead to lateral flow. Because the lateral flow is not conducive to efficient removal of reaction heat, it is desirable to reduce the lateral flow.

thermometer 11 is inserted in the reaction tube, located inside the reactor, and the signal from thermometer 11, may be transferred to the outer side of the reactor to register the temperature distribution in the catalytic layer in the axial direction of the reactor.

Two or more of thermometer can be inserted into the reaction tube for measuring temperature, carrying out measurements in General about the 3 to 20 points on thermometer in the axial direction of the reaction pipe.

The reaction tubes can be grouped into three types depending on their location with regard to the relationship between the reaction tubes and holes in three partitions, i.e. the relationship between the reaction tubes and the direction of coolant flow.

The reaction tube 1A is held only by a partition wall 6b, and not two partitions 6A, since the reaction tube 1A passes through the holes of the partitions 6A. The reaction tube 1A is located in the area where the fluid that passes through the outer surface of the reaction tube rotates back in the Central part of the reactor. The flow of coolant, generally parallel to the axial direction of the reaction tube. The reaction tube 1b is held by three partition walls 6A, 6b, 6A, and most of the reaction tubes are located in this zone.

With regard to the reaction tubes, the direction of coolant flow is nearly perpendicular to the axial direction of the reaction tube on the entire surface of the reaction tube. The reaction tube 1C is located near the outer periphery of the reactor and is located on the outer periphery of the partition walls 6b, and the tube is not held by the partition wall 6b. In the Central part of the reaction tube 1C of the reaction tube 1C is located in the area where the flow changes its direction. In a specific zone, i.e. in the Central part of the reaction tube, the coolant runs parallel to the axial direction of the reaction pipe.

Figure 4 shows a top view of the reactor according to Fig 1.

The Central and outer part of the reactor corresponds to the zone in which the coolant is concentrated through the holes in the walls 6A and 6b and which are the reaction tubes 1A and 1C. Therefore, the area provides not only the flow of fluid in a direction parallel to the axes of the respective pipes, but also there is a sharp decrease in the rate of flow of coolant. In this zone, therefore, the coefficient of heat transfer fluid has a tendency to decrease.

As for the partitions used in the present invention, the partition wall 6A has a hole near the Central part of the reactor vessel. Also, the partition wall 6b is open between the outer periphery and the outer cylindrical wall of the housing. Because the fluid can change its direction around each hole can be protected from the formation side of the coolant flow and can change the flow rate, there may be used any of the partitions, such as segmental walls round shape presented in figure 2, and partition the disk type presented in figure 3. Both types of partitions does not violate the relationship between the direction of the flow of the heat carrier and the axis of the reaction tube.

In particular, partition type drive is used more often than other forms of partitions. The square holes in the Central part of the partition wall 6A is preferably 5-50%, more preferably 10-30%, of the cross-sectional area of the reactor vessel. The area of the passage between the partition wall 6b and the wall 2 of the reactor vessel is preferably 5-50%, more preferably 10-30%, of the cross-sectional area of the reactor vessel. If the ratio of the open areas of the walls (6A and 6b) is too low, increase the pressure loss between the circular pipes (3A and 3b), occurring as expanding the passage of coolant flow, resulting in increased energy demand for the circulation of coolant through the pump 7. If the ratio of the open areas of the partitions is too large, it usually leads to an increase in the number of reaction tubes (1A and 1C), located in the area where the coefficient of heat transfer tends to decrease.

In most cases, the distance between the set partitions (the distance between the partition walls 6A and 6b and the distance between the partition wall 6A and tube sheets 5A and 5b) are equal to each other. However, there is no need to make them equal. Distance can be defined in such a way as to provide the specified flow rate teplonositel is, which is determined by the heat of the oxidation reaction occurring in the reaction tube, while minimizing the pressure loss of the coolant. In addition, you should avoid the septum matched the peak temperature value, which means the highest temperature among the temperature distribution in the catalytic layers located in the reaction tube. The heat transfer coefficient is lower near the surface of the partition, since the flow velocity of the fluid near the surface of the walls is reduced. Thus, when the position of the partition corresponds to the peak temperature occurs subsequent increase in temperature in this part.

To avoid conformity peak values of temperature and position of the walls, you might consider using computer simulation described above.

According to the present invention, the gaseous mixture of water vapor with propylene, propane, isobutylene and/or (meth)acrolein and a gas containing molecular oxygen, is introduced into Novotrubny reactor as the source of gaseous material.

The concentration of propylene, propane or isobutylene in the original gaseous material is 3-15%. The molar oxygen concentration above 1.5-2.5 times, and the molar concentration of the vapors of the odes in the 0.8-2 times higher than the concentration of propylene, propane or isobutylene.

Introduced gaseous source material is distributed in the respective reaction tubes 1A, 1b, 1C, etc. and then passes through the reaction tube for performing the reaction under oxidizing conditions in the presence of a catalyst, is introduced into each of the reaction tubes.

According to the invention, the catalysts used in the reaction of catalytic oxidation in the vapor phase. For example, the catalysts used for the oxidation of propylene, propane or isobutylene and for oxidation of (meth)acrolein, can only be the catalysts commonly used for this purpose, and examples of such catalysts are catalyst system containing Mo, Bi, Sb, etc.

Preferably the reaction tube filled with the catalyst after changing the activity of the catalyst in order to prevent the formation of hot spots and accumulation of heat in them. There are many ways to change the activity of the catalyst in the reaction tube. More specifically, these methods include one way in which use different types of catalysts, and the other way which is provided by the regulation of the activity of the catalyst by mixing and dilution of the catalyst with an inert substance. For example, a portion of the reaction pipe, enter the source gas is brasego material, can be filled with a catalyst containing a high proportion of inert substances, and the output part of the reaction tube can be filled with a catalyst containing a low proportion of inert substances or undiluted catalyst.

In addition, the catalyst activity can be changed in each reaction tube in addition to changing the activity of the catalyst only in a single reaction tube.

The degree of dilution of the catalyst in all of the reaction tubes should not be equal. For example, the reaction tube 1A, located in the Central part of the reactor vessel will have a high temperature peak (part, with the highest temperature of the catalytic layer in the reaction tube). To avoid this phenomenon, the proportion of the inert substance may be increased more than in other reaction tubes (1b, 1C)located in other parts of the reactor. Therefore, it is preferable that the degree of dilution of the catalyst in each reaction tube must be modified to achieve a uniform level degree of conversion of all reaction tubes.

For inert substances used in the present invention, there are no special restrictions, if only it was a substance that would be stable under the reaction conditions and has not entered into reaction with the raw material and finished product.

More specifically inert substances can be those which are used as carriers for catalysts, such as alumina, silicon carbide, silica, zirconium oxide and titanium oxide. In addition, as in the case of the catalyst, the form of the medium is not limited. For example, they may have a spherical, cylindrical shape, a ring shape and an indefinite shape. In addition, the dimensions of the media can be determined based on the diameter of the reaction tube and differential pressure.

In most cases, used as a coolant Niter, which is a mixture of nitrates, which flows down the side of the reactor. In addition, can be used as a coolant, any organic liquid based on the simple phenyl ether. The flow of coolant removes the reaction heat from the reaction tube. However, the coolant introduced into the reactor vessel along the circular pipe 3A inlet coolant has a plot of flow, where the fluid passes from the outer periphery of the reactor to the Central part, and the area where the carrier is rotated around the Central part. When the direction of fluid perpendicular to the axis of the reaction tube, the heat transfer coefficient is usually 1000-2000 W/(m²·). When the Niter is used as the coolant, the heat transfer coefficient can be from 100 to 30 W/(m ²·K), although the value of the coefficient depends on the flow velocity, the upward or downward flow, if the flow direction is not perpendicular to the axis.

On the other hand, the coefficient of heat transfer catalyst layer in the reaction tube is nearly equal to 100 W/(m²·K), although it definitely depends on the speed of flow of the gaseous source material. When flow is perpendicular to the axis of the reaction tube, the heat transfer coefficient of the fluid outside the pipe above 10-20 times than the heat transfer coefficient of the catalytic layer in the pipe.

Therefore, the change in velocity of the coolant flow has little effect on the overall heat transfer coefficient (here, the overall heat transfer coefficient of the mean heat transfer coefficient, calculated with respect to various conditions, including the heat transfer coefficient of the coolant outside of the reaction tubes, the heat transfer coefficient of the catalytic layer in the reaction tube, the conductivity of the reaction tube and the thickness of the reaction tube). However, when the coolant runs parallel to the pipe axis, the coefficients of heat transfer outside the reaction tube and the inside of it almost equal to each other. Thus, the removal efficiency of heat greatly affects the state of the liquid medium outside the Rea the supply pipe. So, when the coefficient of the fluid outside the pipe is 100 W/(m²·K), then the overall heat transfer coefficient of thermal environment is almost half the value of 1000-2000 W/(m²·). The decrease of the coefficient of heat transfer fluid outside the pipe has a large impact on the overall heat transfer coefficient. Therefore, when considering the heat transfer coefficient outside the reaction tube and the inside of it, it is necessary to study the conditions for the exercise of catalytic oxidation in the vapor phase.

The inner diameter of the reaction tube novotrubnogo reactor according to the present invention is preferably 10 to 50 mm, more preferably 20-30 mm, although its value depends on the amount of reaction heat in the reaction tube and the size of the catalyst particles. If the internal diameter of the reaction tube is too small, then the number of the loaded catalyst is reduced. Thus, the number of reaction tubes is increased with respect to the desired amount of catalyst, resulting in increased size of the reactor. On the other hand, if the inner diameter of the reaction tube is too large, the surface area of the reaction tube is reduced with respect to the desired amount of catalyst. Thus, the area of heat transfer to remove the reaction heat is meniaetsa.

Figure 5 shows Novotrubny reactor containing reactor vessel, separated by an intermediate tube plate 9, and the method carried out in this reactor, which is a method of catalytic oxidation in the vapor phase according to the invention.

In the respective divided spaces circulate various coolants, and temperature of the coolant is set different. The source of gaseous material may be introduced through either 4A or 4b. The source of gaseous material supplied through the inlet, responds consistently in the reaction tubes of the reactor.

In novotrubnom reactor depicted in Figure 5, the upper and lower zones of the reactor, separated by an intermediate tube plate 9, contain fluid at different temperatures. Thus, there are the following different situations:

1) the same catalyst fills the entire reaction tube, and the reactions take place at different temperatures in the atmosphere is the source of gaseous material, respectively at the inlet and outlet pipes.

2) the catalyst filled portion of the tube, where does the source of gaseous material, at the same time the catalyst is not present in the output part, thus, the output part remains as an empty pipe or she is filled with an inert material that does not have the reaction is ionic activity in order to quickly cool the reaction product;

3) various catalysts fill respectively the inlet pipe to enter the source of gaseous material and the output of the tube, the catalyst is not loaded in the portion of the pipe between the input and output of its parts, thus, part of the pipe is empty or this part should be filled with an inert material that does not have reactivity, in order to quickly cool the reaction product.

For example, a gaseous mixture consisting of a gas containing molecular oxygen, propylene, propane or isobutylene, may be injected through the inlet for supplying the source material in Novotrubny reactor according to Figure 5, used in the present invention to obtain a first (meth)acrolein at the preliminary stage, i.e. at an earlier stage of the reaction. (Meth)acrolein is then oxidised in the second stage, i.e. at a later stage reaction to produce (meth)acrylic acid. The first stage and the second stage is carried out in a reaction tube, in use, respectively, different catalysts. These first and second stages occur at different temperatures in order to perform the reaction under optimal conditions. Part of the pipe located between the part reserved for the preliminary stage, and a part reserved for the last the ment stage, and in which the intermediate tubular lattice, preferably filled with an inert material that does not participate in the reaction.

Figure 6 shows a zoomed view of the intermediate tube. Although part of the pipe designated for the preliminary stage, and the portion of pipe designated for the subsequent stage, was regulated at different temperatures, when the temperature difference exceeded 100°With, the transfer of heat from the high temperature heating medium to the heat medium of low temperature became too large to ignore, and accuracy of the reaction temperature at low temperatures tends to decrease. In this case, it is necessary to provide thermal insulation to avoid heat transfer above and below the intermediate tube. Figure 6 shows an insulating plate. The insulating effect is obtained preferably by using two or three heat shield panels 10, located at a distance of about 10 cm above or below the intermediate tube with the formation of stagnant zones 12, which is then filled with fluid that is not moving. Heat shield panel 10 can be fastened to the intermediate pipe grid 9 by using, for example, the spacer rod 13.

Although the arrows in figures 1 and 5 show that the flow direction of the coolant in to the Ruse reactor is rising, the thread can be moved in the opposite direction according to the present invention. The decision on the areas in which circulates the coolant flow should be adopted so as to avoid the phenomenon of capture of particles, in which the flow of coolant carries away the gases, particularly inert gases such as nitrogen, which can be located in the upper part of the reactor 2 and the circulating pump 7. When the coolant reaches the highest point (Figure 1), may occur the phenomenon of cavitation caused by the entrainment of gas in the upper part of the circulating pump 7, and the pump fails in the worst case. When the flow of coolant is flowing, the phenomenon of entrainment of gas can occur in the upper part of the reactor with a retention there of particles in the gas phase. The upper part of the reaction tubes, around which gather charged gas particles will not be cooled by the coolant.

In order to protect the reactor from the gas retention, you need to install a pipeline to extract gas to replace the gas in the gas layers coolant. To this end, the pressure in the housing must be high due to the pressure of fluid in the pipe 8A coolant and by setting as high as possible pipeline 8b removal of the coolant. It is preferable to set the Tr is borrowed removal of the heat carrier at least above the tube 5A.

When Novotrubny the reactor shown in figure 1, is used as novotrubnogo reactor for the oxidation of propylene, propane or isobutylene gas containing molecular oxygen, and is used downward flow of the reaction gas, in other words, when the source of gaseous material enters through 4b, and the product goes through 4A, the concentration of the target product (meth)acrolein in the reactor is high near the outlet of product 4A. In this case, the temperature of the reaction gas is also higher due to heat of reaction. Therefore, in this case, it is preferable to have the reaction gas is sufficiently cooled using a heat exchanger that is installed behind 4A in the reactor according to Fig 1 in order to eliminate the reaction of autoxidation (meth)acrolein (reaction autolysis).

When Novotrubny reactor depicted in Figure 5, is applied with a downward flow of the reaction gas, in other words, when the original gaseous material passes through 4b and the product goes through 4A, the concentration of the target product (meth)acrolein high near the intermediate tube 9, which indicates the end of the reaction in the first stage. Therefore, the temperature of the reaction gas near the intermediate tube also increases due to heat of reaction. When only the first stage (5A-6A-6b-6A-9) IP is alzueta catalyst, the reaction tube 1A, 1b and 1C in the second stage (from 9 to 5b) does not participate in the reaction and the reaction gas is cooled by the coolant flowing in the pipelines on the surface of the body for elimination reaction of autoxidation (meth)acrolein. In this case, the reaction tubes 1A, 1b and 1 (from 9 to 5b) are empty, without any catalyst, or filled with a solid material having no reactive activity. The latter is preferable for improving the properties of the fluid.

When using different catalysts in the first stage (5A-6A-6b-6A-9) and in the second stage (9-6A'-6b'-6A'-5b) in novotrubnom reactor depicted in Figure 5, to obtain a (meth)acrolein of propylene, propane or isobutylene in the first stage and to obtain the (meth)acrylic acid in the second stage, the temperature of the catalytic layer at the first stage becomes higher than the temperature of the catalytic layer to the second stage. It should be noted that as the temperature increases towards the end of the reaction in the first stage (6A-9) and closer to the beginning of the reaction in the second stage (9-6A'), it is preferable that the reaction was not carried out in this part and that the reaction gas was cooled flowing coolant in the pipes on the wall of the body for elimination reaction of autoxidation (meth)acrolein. In this case, part of the tube without any catalyst fo the s near the intermediate tube 9 (between 6A-9 6A' of the reaction tubes 1a, 1b and 1c), and must be empty or be filled with a solid material having no reactive activity. This latter is preferable for improving the properties of the fluid.

Examples

Hereinafter, the present invention is described more specifically with reference to examples. Needless to say that the present invention is not limited to the given examples.

Example 1

To prepare for the oxidation of propylene was obtained powdery catalyst having the following composition: Mo(12)Bi(5)Ni(3)Co(2)Fe(0,4)Na(0,2)B(0,4)K(0,1)Si(24)O(x),

As a catalyst for the preliminary stage of the method (in composition x of the oxygen has a value determined by the oxidation state of each metal), the catalyst was used in the form of a ring with an outer diameter of 5 mm, an inner diameter of 2 mm and a height of 4 mm and was obtained by molding a powder of the catalyst.

Used reactor shown in figure 1, in which case the reactor had an inner diameter 4500 mm, equipped with 12000 reaction tube made of stainless steel, each of the reaction tubes had a length of 3.5 m, an internal diameter of 24 mm and an outer diameter of 28 mm

Niter, the molten mixture of salts of nitrate, was used as a coolant and served through the lower part of the reactor.

Coolant temperature showed the temperature at which is was odwalla in the reactor coolant. The reactor was operating at a flow rate of coolant 2500 m²/hour.

Analysis of coolant flow simulation was performed using the software CFX4 for flow analysis (developed by AEA Technology Plc), taking into account such parameters as the size and location of the reaction pipe, the velocity of the injected gas and the flow rate of the coolant. The analysis showed the presence of a zone with a heat transfer coefficient equal to 500-900 watts/(m²·K) in the Central part of the reactor, and in other parts of the heat transfer coefficient was 1000-1600 W/(m²·).

Each reaction tube in the zone of reactor heat transfer coefficient, equal 500-900 watts/(m²·K), closed by a metal lid to avoid leakage of gas.

Each of the remaining reaction tubes were filled to a volume of 1.5 liters of a catalyst, described above, to conduct a preliminary stage.

The source gas containing propylene in a concentration of 9%vol., moved in the upper part of the reactor when the pressure is prescribed at the level of 75 kPa. The temperature distribution in the reaction tube was measured by the inserted thermometer, with 10 measuring points in the axial direction of the pipe. In particular, the highest temperature was considered as the peak temperature.

After operation of the reactor during the week when the temperature is warm the carrier 330° With the conversion of propylene was 97%, the total yield of acrolein and acrylic acid was 92% and the peak temperature in the catalytic layers involved in the reaction, was 385°C.

Comparative example 1

In the area of low coefficient of heat transfer, comprising 500-900 watts/(m²·K), as described in example 1, the reaction tubes were removed the metal cover. The test was performed under the conditions described in example 1, except that each of the reaction tubes in this area was loaded in a volume of 1.5 l of the same catalyst for the preliminary stage, as described in example 1.

The source gas containing propylene in a concentration of 9%vol., served through the upper part of the reactor when the pressure of 75 kPa. The temperature distribution in the reaction tube was measured using a thermometer 10 measuring points along the length of the pipe.

After operation of the reactor during the week when the temperature of the heat carrier 330°With conversion of propylene was 95%. The total yield of acrolein and acrylic acid was 89% and the peak temperature in the catalytic layer, participating in the reaction, 430°in the Central part of the reactor and 385°in other parts of the reactor.

Industrial application

In accordance with the present invention, a method of catalytic oxidation in steam FASEB conditions, in which the coefficients of heat transfer is 1000 W/(m²·K) or higher, the method is carried out in novotrubnom the reactor, which enables the effective removal of reaction heat, prevents the formation of hot spots, provides efficient retrieval of the target product and prolongs the service life of the catalyst, reducing its catalytic activity.

1. Method of catalytic oxidation in the vapor phase (and) propylene, propane or isobutylene with molecular oxygen to produce (meth)acrolein and/or oxidation (b) (meth)acrolein molecular oxygen to obtain a (meth)acrylic acid with novotrubnogo reactor containing a cylindrical reactor vessel equipped with inlet port for supplying the source material and the discharge of the product, many of the circulation pipes located around the cylindrical reactor and used for the introduction of fluid into the cylindrical reactor vessel for removing the coolant circulating device for connection of a variety of circular pipes each with each other, many of the reaction pipes installed using a variety of pipe arrays reactor that holds the catalyst, and a lot of partitions arranged in the longitudinal direction of the reaction t the UBA and used for changing the direction of fluid introduced in the reactor vessel, whereby analyze the flow of coolant and define the zones in the reactor in which the heat transfer coefficient of the coolant is less than 1000 W/(m²·K); prevent the reaction of catalytic oxidation in the vapor phase in the specified zones of the reactor and carry out the reaction of catalytic oxidation in the vapor phase in the reactor.

2. The method according to claim 1, wherein analyzing the coefficient of heat transfer fluid simulation on the computer.

3. The method according to claim 1, wherein to prevent the reaction of catalytic oxidation in the vapor phase in areas that have a heat transfer coefficient of the coolant less than 1000 W/(m²·K), close the pipe in the area with a heat transfer coefficient of less than 1000 W/(m²·K)to prevent the leakage of gas.